Cystic fibrosis is an inherited multi-system disorder which is characterized by an abnormality in exocrine gland function and which occurs almost exclusively in populations of European origin. The incidence of the disease amongst white Americans, for instance, is between 1/1600 and 1/2000 live births. Amongst black Americans, on the other hand, the incidence is only about 1/17000. Although survival of cystic fibrosis patients has improved in recent years, the median survival is still only about 20 years despite intensive supportive and prophylactic treatment.
Cystic fibrosis is uniformly fatal. Nearly all patients suffering from the disease develop chronic progressive disease of the respiratory system, the most common cause of death being pulmonary disease. Also, in the majority of cases, pancreatic dysfunction occurs; hepatobiliary and genitourinary diseases are also frequent. It is thought that the primary defect of the condition is related to abnormalities of chloride and sodium transport across mucous membranes.
Nedocromil sodium, the disodium salt of 9-ethyl-6,9-dihydro-4,6-dioxo-10-propyl-4H-pyrano(3,2-g)quinoline-2,8-dica rboxylic acid, has been known for some time, eg from British Patent Application No 2157291A, for the treatment of reversible obstructive airways disease by administration as a pressurised aerosol. We have now surprisingly found that administration of 9-ethyl-6,9-dihydro-4,6-dioxo-10-propyl-4H-pyrano(3,2-g)quinoline-2,8-dica rboxylic acid or a pharmaceutically acceptable derivative thereof may be useful in the treatment of cystic fibrosis.